package com.hmdp.utils;


import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {

    /**
     *  开始时间戳
     *   1640995200
     */
    private static final long BEGIN_TIMESTAMP = 1640995200L ;

    /**
     *  序列号的位数
     *
     */
    private static final int COUNT_BITS = 32 ;

    private StringRedisTemplate redisTemplate ;

    public RedisIdWorker(StringRedisTemplate redisTemplate) {
        this.redisTemplate = redisTemplate;
    }

    public Long nextId(String keyPrefix){

        // 1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long epochSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = epochSecond - BEGIN_TIMESTAMP;

        // 2. 生成序列号
        // 2.1 获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        // 2.2 自增长
        long count = redisTemplate.opsForValue().increment("incr:" + keyPrefix + ":" + date);

        // 3. 拼接并返回
        return timestamp << COUNT_BITS | count ;
    }
}
